From Sahih Muslim (Hadith 3146):
Ibn 'Umar reported that Allah's Messenger (ﷺ) said:May Allah have mercy upon those who have got their heads shaved. They said: Messenger of Allah, (what about) those who got their hair clipped? He said: May Allah have mercy upon those who have got their heads shaved. They said: Messenger of Allah, (what about those who have got their hair clipped)? He said: May Allah have mercy upon those who got their hair shaved. They said: Messenger of Allah, (what about) those who got their hair clipped? He said: (O Allah, have mercy upon) those who got their hair clipped
Reference: Muslim 3146